Biotoxin from puffer fish may provide treatment for opioid withdrawal

On November 10, 2004 investigators involved in a Phase IIa clinical trial of the novel biotoxin Tetrodotoxin (TTX) for the treatment of opioid withdrawal enrolled their first participants.

This double-blind, randomized, cross-over, placebo-controlled trial will evaluate the efficacy and safety of Tetrodin™ for treatment withdrawal symptoms in 20 opiate-dependent subjects who are receiving methadone in a treatment program. It is the first study involving a biotoxin for opioid withdrawal to be done in North America.

Use of opioids presents many challenges for the addicts, their families, and society as a whole. The health and social consequences include HIV/AIDS, Hepatitis B, and C, tuberculosis, fetal effects, violence, and crime. Family life, workplace, and educational environments are all affected, with associated costs reaching billions of dollars each year.

"There's a need for new treatments for heroin dependence and for opiate abuse, and this is one potential new approach, directed at modifying the physical dependence that occurs with repeated use of drugs like heroin," said Dr. Edward Sellers President and CEO of Ventana Clinical Research Corporation. Dr. Sellers is the lead investigator on the study, and is a member of numerous national and international editorial boards, governmental advisory committees, and international organizations including the World Health Organization Expert Advisory Committee on Drug Dependence.

What is Opioid Dependence - Why use a Biotoxin?

Opioid dependence is generally characterized by a withdrawal syndrome that occurs when the drug is abruptly discontinued. Managing withdrawal is essential in enabling people to begin treatment programs to end their opioid dependence. The traditional medical management of opioid withdrawal involves substituting long-acting opioids for shorter-acting opioids, and gradually tapering the treatment.

However, unlike traditional therapies Tetrodin™, developed by Wex Pharmaceuticals, is derived from the puffer fish, also known as the blow fish. Studies have shown it to be fast acting, long lasting and non-addictive. It was originally developed for the clinical treatment of heroin withdrawal in China. It works by blocking slow sodium channel nocicipetive pain fibres in a highly selective way. Tetrodotoxin proved to have such good analgesic properties in the initial Chinese trials that it is also now being evaluated for clinical use in the treatment of refractory cancer pain.

"The results from this Phase IIa trial in patients on methadone should be known in 2005. "The study is going well. I expect early next year to know whether this works out or not. One could be hopeful that it represents a new treatment," Dr. Sellers said.